Modular secondary connector

ABSTRACT

Modular insulated connector for add-on underground residential distribution systems.

United States Patent Jane: A. Slevert Stilnter, Mlnn. 860,228 Sept. 23.1969 June 15, 1971 Minnesota Mining and Manufacturing p y I St. Paul,Minn.

lnventor App]. No. Filed Patented Assignee MODULAR SECONDARY CONNECTOR 41 cum, 3 Drawing Flgs.

as. m 339/22, 339119.339/59, 339/242, 339/263 1.1.01 non 11/02 [50]Fieldol Search; 339/19, 22,

59, 60, 61,198, 277, 241, 242, 263, 5, 211 [56] References Cited UNITEDSTATES PATENTS 1,128,405 2/1915 Brooks 339/19 3,480,905 1 1/1969Toedtman 339/213 Primary Examiner-Marvin A. Champion AssistantExaminer-Robert A. Hafer Attorney-Kinney, Alexander, Sell, Steldt andDelahunt ABSTRACT: Modular insulated connector for add-on undergroundresidential distribution systems.

MODULAR SECONDARY CONNECTOR This invention relates to electricalconnectors and in particular to preinsulated modular secondaryconnectors for underground residential distribution systems.

Multiple tap insulated connectors for making secondary or low voltageconnection between a supply line and a number of residentialinstallations are known. Unused taps remain available for subsequentconnection to new installations. Since they must be thoroughly insulatedwhen not in use, the insulation must first be removed when a newconnection is desired. Since the several leads are permanentlypositioned, connecting cables must be first maneuvered into position topermit forming the connection. Only a fixed number of connections ispossible, and surplus taps are therefore commonly provided for possiblesubsequent use.

The present invention provides a modular connector'capable of acceptingany desired number of tap connection modules within the current-carryingcapacity of the system. Each module is self-insulated and is easily andquickly introduced into the assembly without requiring preliminaryremoval of insulation. The modules may be placed in any desireddirection. Since modules are added only as required, no surplus taps arenecessary.

A presently preferred form of the invention is illustrated in theaccompanying drawing, in which:

FIG. 1 is a plan view, partly cut away to show interior detail, of amodular secondary connector having three taps,

FIG. 2 is a sectional view taken approximately at line 2-2 of FIG. 1,and

FIG. 3 is a sectional view taken approximately at line 3-3 of FIG. 1.

The assembly of FIG. 1 will be seen to consist of three T- connectiontap modules 11, 12, 13 held together with a bolt 14 and nut 15. Forpurposes of illustration the three modules each have a different cablecontact extension; but it will be apparent that any combination of suchelements may equally well be used. By selection of a bolt of suitablelength it will also be apparent that any number of modules may besecured together.

As more specifically shown in FIG. 2 for module 11, the module comprisesan annular body 16 having flat parallel end faces and a radial extensionforming an elongate terminal 17, and covered with a rubbery insulatingcoating 18. In the relaxed position the rubbery coating extendsbeyondthe flat end faces of the annular body 16 a distance sufficient toprovide a water-impenetrable seal when two adjacent modules are drawninto metal-to-metal contact by the bolt 14 and nut 15.

Full conductive contact between modules may be achieved by face-to-facecontact as shown between modules 12 and 13. The simple structure thereindicated provides maximum economy and is entirely adequate where aspecified number of modules are to be permanently combined.

An alternative structure, shown at the juncture of modules 11 and 12 inFIG. 1 and in lateral cross section in FIG. 3, cmploys a doubly taperedseize ring 19 fitting within correspondingly tapered annular channels20, 21 in the opposing faces of the two modules. Once the modules areforced together, the ring 19 becomes permanently seized or welded to theannular bodies to form a permanent junction. The bolt 14 may then bewithdrawn without separation of the modules, thereby facilitating theinsertion of a longer boltand the addition of further modules asdesired.

Terminal 17 is illustrated in FIGS. 1 and 2 as a simple crimp typetubular terminal for making permanent contact with a bar cable-end bymechanical crimping. The insulation 18 in this case covers only thefirst portion of the terminal. The terminal 17 of module 12 has atapered socketlike open interior for accepting a tapered terminal plug,not shown. A key 22 fitting within a hole in the sidewall is urgedinwardly by the elastic covering 18' for retaining the suitably groovedplug. The insulating covering 18 extends slightly beyond the open end ofthe terminal 17 and is constricted to provide'a tight seal over theconnecting plug or cable. The terminal 17" of module 13 consists of ahalf cylinder which mates with a corresponding half-cylinder terminalplug, not shown, being held in close contact therewith by a screw 23.

Particularly in the case of modules 11 and 13 as illustrated it will beappreciated that the terminal and the cable are to be provided withfurther sealants, insulating and protective coverings, and the like atthe area of contact, e.g. by wrapping with rubbery adherent stripmaterial, or by covering with an elastic tube, or by other means.

The head 24 of the bolt 14 is pennanently covered with an insulating cap25 bonded thereto and which, similarly to the coverings 18, extendsslightly beyond the fiat forward face of the head and when placed undercompression forrns'a tight seal with said covering. The nut 15 is alsocovered with a tightly fitting insulating covering 26. In order topermit tightening of the nut 15, the covering 26 is supplied as aseparate component which is snapped over the nut after the connector hasbeen otherwise assembled. An inner ridge 27 fits into a peripheralgroove 28 in the nut for this purpose.

In a typical example, the annular ring 16 has an outer diameter of 1.25inch (31.6 mm.) and an inner diameter of 0.65 inch (16.5 mm.), and is1.80 inches (4.6 cm.) between the two end faces. The terminal 17 extendsa total of 3.50 inches (8.9 cm.) fromthe center of the ring and has anouter diameter of l inch (2.5 cm.). The modules are mounted on a 95-inch15.4 mm.) bolt. All metal parts are of aluminum. The insulating coveringhas a minimum thickness of about oneeighth inch (4 mm.) and is a hardrubbery material, preferably of Nordel ethylene-propylene terpolymer,having a Shore A densometer value of about 60. The polymer coatingextends about 0.03 inch (0.75 mm.) past the contacting metal surface ineach instance, and is lightly beveled at the edges so that fullmetal-to-metal contact may be attained.

What I claim is:

l. A module for a modular secondary connector comprising an annularmetal body having flat parallel end faces and a radial extension forminga cable-receiving terminal, and an elastomeric insulating coating oversaid body and at least the first portion of said extension and extendingfractionally past the plane of each of said faces.

2. The module of claim 1 wherein said body is provided with an annularlightly tapered channel at each of said faces, and including a doublylightly tapered seize ring fitting within one .of said channels and theopposite channel of an adjacent module.

3. A modular assembly of a plurality of modules as defined in claim 1including terminally insulated bolt and nut means holding said modulesin tight face-to-face contact.

4. A modular assembly of a plurality of modules as defined in claim 2including terminally insulated bolt and nut means holding said modulesin tight face-to-face contact.

5. The assembly of claim 3 wherein said nut is circumferentiallyexteriorly grooved and is covered with a correspondingly internallyridged insulative elastomeric cap.

6. Method of connecting cables suitable for use in undergroundresidential distribution systems comprising connecting each said cableto a connector module as defined in claim 1, insulatively protecting theconnection, and assembling said modules together under compressionsufficient to provide tight conductive contact between adjacent faces ofsaid modules and to compress the adjacent fractional extensions of saidinsulating coatings to form a water-impenetrable seal.

7. Method of connecting cables suitable for use in un dergroundresidential distribution systems comprising connecting each said cableto a connector module as defined in claim 2, insulatively protecting theconnection, assembling said modules with an intervening seize ringbetween each two adjacent modules along a central support, andcompressing modules and ring together under pressure sufficient to causeseizure of said rings in said modules and permanent Eoii ductive contactbetween said modules and to compress the adjacent fractional extensionsof said insulating coatings to form a water-impenetrable seal.

1. A module for a modular secondary connector comprising an annularmetal body having flat parallel end faces and a radial extension forminga cable-receiving terminal, and an elastomeric insulating coating oversaid body and at least the first portion of said extension and extendingfractionally past the plane of each of said faces.
 2. The module ofclaim 1 wherein said body is provided with an annular lightly taperedchannel at each of said faces, and including a doubly lightly taperedseize ring fitting within one of said channels and the opposite channelof an adjacent module.
 3. A modular assembly of a plurality of modulesas defined in claim 1 including terminally insulated bolt and nut meansholding said modules in tight face-to-face contact.
 4. A modularassembly of a plurality of modules as defined in claim 2 includingterminally insulated bolt and nut means holding said modules in tightface-to-face contact.
 5. The assembly of claim 3 wherein said nut iscircumferentially exteriorly grooved and is covered with acorrespondingly internally ridged insulative elastomeric cap.
 6. Methodof connecting cables suitable for use in underground residentialdistribution systems comprising cOnnecting each said cable to aconnector module as defined in claim 1, insulatively protecting theconnection, and assembling said modules together under compressionsufficient to provide tight conductive contact between adjacent faces ofsaid modules and to compress the adjacent fractional extensions of saidinsulating coatings to form a water-impenetrable seal.
 7. Method ofconnecting cables suitable for use in underground residentialdistribution systems comprising connecting each said cable to aconnector module as defined in claim 2, insulatively protecting theconnection, assembling said modules with an intervening seize ringbetween each two adjacent modules along a central support, andcompressing said modules and ring together under pressure sufficient tocause seizure of said rings in said modules and permanent conductivecontact between said modules and to compress the adjacent fractionalextensions of said insulating coatings to form a water-impenetrableseal.